Expansible fabric cover



June 9, 1942. c, R, JOHNSON 2,286,136

EXPANSIBLE FABRIC COVER Original Filed May 16, 1940 Cfiaries RJoknson N ENTOR I BY ATTORNEY Patented Ju t-.9, 1942 t i 3 UNITE,,.];)J STATES' PATENT "oFFicE, p

Charles R. Johnson, Glenn Mills, Pa., asslgnor to E. I. du Pont de Nemours & Company, Wilmington, lleL, a corporation of Delaware Continuation of application Serial No. 335,541,

May 16, 1940. This application December 3,

1940, Serial. No. 368,310-

inner surface is impeded. Also, when extrusion 3 Claims.

This invention relates to improvements in braided, stranded wire fabric covers or jackets for rubber tubes or cartridges suitable for expansion and contraction by means of oil orother fluid under pressure for use in mining operations, and particularly for breaking down coal from a seam in a mine, and for other similar purposes.- g K While braided fabric of stranded wires, particularly when the strands are arranged in sets, are essential for the successful operation of an expansible and contractible cartridge or tube of the character herein described, it-has been found that such a .fabric must form a substantially uniform surface over the entire expansible portion of the inner tube of rubber or similar fiexi-' ble and expansible material so as to prevent the extrusion thereof. thru openings between the strands.

It is the practice in constructing braided wire covers or jackets for mining tubes and the like to use wire strands, but the pressures'used in actual operations, which are well in excess of has once taken place the stranded wires are prevented by the extruded rubber or similar matecover pivot about theirpoints of contact as axes.

2,000 pounds per square inch, cause severe nickand it is at these points that severe nicking occurs, resulting in early failure of the braided cover. While the free lateral movements of the strands are essential at the points marked B and C in order to facilitate closing of'the bpenings which appear in these areas, such lateral movement is absent in the parallel sections or main body portion of the braided cover.

I have found therefore that when a braided wire fabric is'made of stranded wire having the outer surfaces ground away or otherwise removed so as to present a substantially smooth flat surface, the lateral movement of the wires when the fabric is expanded or contracted is not only facilitated-but the nicking of the wires is substantially eliminated and the life of the fabric materially increased. I

tensile wire whensubjected to the high prescovers are made of wire strands having their surfaces ground smooth, with the outer edge or surface of each outermost wire of each strand provided with a substantially flat surface which bears directly against a similar surface of the adjacent strands, nicking of the wires is substantially eliminated and the life of such braided wire structures is materially lengthened,

It will also be seen by reference to Figure 2 of the accompanying drawing that upon inflation or expansion of the cartridge or tube a curved surface or shoulder is formed in the areas marked B and C at each end of the cartridge or tube due to the restrictions of the ends of both the inner tube and the outer braided fabric cover by the securing collars I4 and 16. At these points marked B and 0 there is a greater causing substantially diamond-shaped openings between the strands, and these. openings become larger when the lateral movement of the strandson the outer surface across the strands on the cut as the description proceeds and reference is For example, I have found that a mining tube or cartridgehaving a cover or Jacket of braided wire fabric in which the outer surfaces of the strands are groun'd smooth will withstand expension and contraction under pressures in excess of 2000 pounds per square inch of more than 500 times before breaking of any of the strands, as compared with a similar structure made of braided strands in which the outer surfaces have not been ground or removed to produce a smooth outer surface which withstood under similar conditions only approximately 50 to expansions and contractions before breaki g l A principal object of my invention is to increase substantially the life and usefulness of braided wire covers or jackets made of stranded wires and adapted to be expanded and contracted;

Another object of my invention is to eliminate nicking of the outer wires in covers or jackets made of braided strands of wires.

A further object is to facilitate the unimpeded movement of the sets of stranded wires laterally across similar sets during expansion and contraction of the braided fabric.

These and other objects will be more apparmade to the accompanying drawing, in .which-:.

Figure 1 is an elevational view of an unexpanded tube having a braided wire structure surrounding the tube;

Figure 2 is a view in elevation of the eirpanded;

cover and tubes togethenaccording to estab lished practice. As shown, the tubular braid I2 is made up of sets of three strands each carried alternately over and under three similar sets of wire strands. Figure 2 shows the tube and cover expanded. c

In Figure 3 the outer strands of wires are shown withthe metal removed at the points designated 20 and 22 to provide a substantially smooth outer surface. These wire strands may be made in the usual way either with wires of the same diameter, or wires of varying diameter, as shown in Figure 3, by having the outer surfaces of the outermost wires reduced to a substantially flat or slightly curved surface so as to eliminate nicking of the wires when the strands are forced under extreme pressure one against the other.

My improvement is especially applicable to any braided wire jacket or tubular cover where increased life of the braided wire fabric is desired, but is particularly applicable to covers or jackets made of wire strands arranged in sets carried over and under each other to form a tubular expansible and contractible braid. Such tubes or cartridges forming the inner element of each unit comprise a tube or bag of rubber or similar material as shown in Figure 1 so constructed as to permit expansion or contraction by means of the application or withdrawal of a fluid, and preferably by the use of hydraulic pressure which may run preferably in excess of 2,000 pounds per square inch.

This is a continuation of my application Serial No. 335,541, filed May 16, 1940.

While I have shown and described one specific embodiment of my'invention, it will be understood that various modifications may be made without departing from the scope of my invention and that I do not intend to be limited except as indicated in the following patent claims:

I claim:

1.'An expansible and contractible braided metal tubular cover or jacket for reinforcing expansible and contractible hollow bodies of elastic material, comprising braided strands of wire having the outer surfaces .of the strands reduced to substantial smoothness to eliminate nicking of the strands in line contact when sub- .iected to high pressure from within the tubular 2. An expansible contractible tubular metal cover for reinforcing expansible and contractibl hollow bodies of elastic material, comprising braided sets of wire strands having the outer surfaces of the strands reduced to substantial smoothness to eliminate nicking of the strands in line contact when subjected to high pressure from within the tubular cover and to eliminate subsequent weakening of the strands resulting from rotation of the strands about their points of contact as an axis during subsequent expansions of the tubular cover.

3. An expansible tubular cover for reinforcing expansible bodies such as mining cartridges and the like, comprising sets of strands eachof which sets consists of atleast three strands and each of which sets is carried alternately over and under at least three of the other sets to form a tubular expansible braid, with end fittings to which the ends of the braid are secured, and having the outer surfaces of the strands ground to substantial smoothness to eliminate nicking of the wires at their points of contact when subjectedto high pressures and to eliminate sub-' sequent weakening of the strands as they are rotated about their points of contact as an axis during subsequent expansions of the tubular cover. I

CHARLES R. JOHNSON.

. CERTIFICATE OF CORRECTION.

{at'ent No. 2,286,136. June 95 191mm CHARLES R. JOHN It ishereby certifie'dthat Qexgror 'appeera in the-printed a ivecif'icadalonv of fhe abeve mmberegpat'e'nt reqxiiring eerrection aa follows: Page. 1, first column, line 514., after v "their" insert "miter"; and that the said Letters Patent should be read with-this eorr'ectibn therein that the same may conform to the record of the use in the mum: 'o'rri'c.

sighed and peeled this hth day of Aujguat, A. D. 19142.

, Hefirwflen-Arsdale, (Seal) 1 Acting Commissioner of Patents. 

